16km to the northeast of Didymoticho and on the banks of Evros lies the village Pythio, which during the Byzantine era had the name Empythion. The Byzantine castle, built in 1291, is preserved here intact and it has been used as a shelter and the treasury (register) of Emperor Ioannis Katakouzinos. Moreover, it has two towers, one three stories high and the other four.  Free admission.